<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>css3-变量</title>
    <link rel="stylesheet" href="./style/index.css">
</head>
<body>
    <div>
        我是div里面的文字
    </div>
    <!-- <script>

        // 获取
        getComputedStyle(document.documentElement).getPropertyValue('--bg-color')  // lightblue
        
        // 赋值
        document.documentElement.style.setProperty('--bg-color', 'yellowgreen')
    </script> -->
</body>
</html>